• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.3
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• pp.182-191
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• 2020

A field test and a phytotron study were performed over two years to examine whether rice varieties originated from higher altitude areas have lower optimum grain filling temperatures for yield improvement than the varieties from South Korea. Three varieties originated from North Korea and three varieties from northern China were compared to the same number of varieties from South Korea. In a field study, the optimum grain filling temperatures over 40 days after heading were 22.6 - 23.0℃, 21.5 - 22.3℃, and 21.5 - 23.6℃ for the varieties from North Korea, northern China, and South Korea, respectively, resulting in no significant difference among varietal groups. Meanwhile, the heading dates of the early maturing varieties from North Korea and China were 7 - 12 days earlier than that of the early maturing Odae variety from South Korea during the first transplant of 2017. The phytotron study, in which different temperature regimes were imposed from flowering/fertilization to harvest with constant daily mean temperatures, revealed that milled rice weight did not decrease under low temperatures, even at 16℃, compared to that at 22℃. At the fourth transplant in the field study, mean temperature lower than 10℃ appeared before rice grains were fully developed, resulting in yield reductions. It was concluded that rice varieties adaptable to high-altitude areas do not have lower optimum grain filling temperatures but, instead, possess shorter growth durations. It was further suggested that the optimum grain filling temperature of rice observed under natural conditions could be attributed to the lowering temperature at the late filling stage under temperate climatic conditions.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.648-652
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• 2005

A super ionic conductor, $K^+$-beta-aluminas, which is known to be difficult to obtain in the form of dense sintered density under atmospheric pressure, was pulverized to 350 nm mean particle size using attrition mill. The sample were pressed into tablet form by uniaxial pressing. The specimen was sintered under atmospheric pressure in powder form. Sintering temperature range was $1400^{\circ}C$ to $1650^{\circ}C$ at $50^{\circ}C$ intervals. Additionally, zone sintering was carried out to control the growth grain at high temperature ($1600^{\circ}C$). The density of specimens that were sintered at $1600^{\circ}C$ and $1650^{\circ}C$, and sintered at $1600^{\circ}C$ by zone sintering were about 93% and 95%, respectively. In the case of the lengthened sintering time to 2 h, the density of specimen was reduced to lower than 90%, since the particles were grown to the duplex microstructure.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.42-46
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• 2006

The purpose of this study was to assess whether mechanical sensory score by Toyo Midometer can be substituted by near-infrared spectroscopy (NIRS) method in whole-grain milled rice samples. Toyo values of collected commercial brand rice (n=127) had comparatively wide ranges from 62.9 to 84.2 (Mean=70.5; S.D.=4.0). Calibration equation was developed using 73 samples. Standard error of calibration (SEC) for sensory score equation and $R^2$ were 0.95, and 0.94, respectively, however, percentage of variation in the reference method values (1-VR) which give a true indication of equation performance was slightly lower (1-VR=0.81) than calibration equation. It was demonstrated that, even though NIRS has potential as a rapid tools to predict rice sensory score, the prediction of sensory score in rice by NIRS needs to be further investigation on a large number of sample with different varieties and growing locations.

• Applied Biological Chemistry
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• v.44 no.3
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• pp.179-184
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• 2001

To investigate the effects of harvesting times on physicochemical and milling properties of rice, milling tests were performed applying laboratory milling systems. Milling and head rice yields were highest in rice harvested at the 45 days after heading at 76.49 and 94.43%, respectively. Milled rice grain harvested 45 days after heading showed the highest minimum viscosity, as shown in the amylogram curves, as well as the lowest consistency viscosity. Protein and amylose contents were highest in rice harvested at 35 days after heading, whereas the instrumental taste score was highest 45 days after heading.

• Korean Journal of Food Science and Technology
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• v.18 no.2
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• pp.143-148
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• 1986

The composition of glycolipids and phospholipids of milled rice grain were studied for four nonglutinous and two glutinous varieties grown in Korea. Main classes of the glycolipids were esterified sterylglycosides, monogalactosyl diglycerides, steryl glycosides, digalactosyl diglycerides and cerebrosides in both of nonglutinous and glutinous, and no differences in individual content of the classes between both varieties. Of the phospholipids, Iysophophatidyl cholines, phosphatidyl cholines, phosphatidyl ethanolamines, phosphatidyl inositols and phosphatidyl serines were the major components, comprising oveer 85% of this class, and smaller amounts of diphosphatidyl glycerols and phosphatidyl glycerols were present. There was significant differences individual content of the phospholipid classes between both varieties. The major fatty acids of glycolipids and phospholipids fractions were palmitic, linoleic and oleic acids in both of nonglutinous and glutinous varieties. But content of palmitic acid in glycolipids fraction and stearic, oleic and linoleic acids in phospholipids fraction showed significant differences between both varieties.

• Korean Journal of Food Science and Technology
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• v.18 no.2
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• pp.137-142
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• 1986

The lipids content and neutral lipid component of milled rice grain were studied for four nonglutionous and two glutinous varieties grown in Korea. The average total lipid contents in nonglutinous and glutinous varieties were 0.94% and 1.78% by dry weight basis, respectively. The ratios of neutral lipid, glycolipid and phospholipid in the total lipid were 76.5 : 14.8 : 8.6 in the nonglutionous and 82.4 : 11.1 : 6.5 in the glutinous, respectively. Main classes of the neutral lipids were triglycerides, free fatty acids, steryl esters, free sterols, monoglycerids and diglycerides in both of nonglutinous and glutinous, and no significance was observed in the content of the classes between both varieties. The major fatty acid composition of total and neutral lipids were linoleic, oleic and palmitic acids in both of nonglutinous and glutinous varieties.

• Food Science and Preservation
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• v.15 no.2
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• pp.219-224
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• 2008

"Charmdlerak" a new high-quality Korean wheat, was produced with production management from the Rural Development Administration (RDA). We evaluated the characteristics of grain, flour, and end-use quality of "Charmdlerak" wheat to assess consumer satisfaction with this new variety of wheat. Eighty-two farmers (450MT/100 ha) in Gwangju metropolitan city produced Keumkangmil wheat and 23 farmers (30 ha) produced "Charmdlerak" wheat "Charmdlerak" wheat had 1.55% ash content and 11.0-13.0% protein content "Charmdlerak" flour was milled by a commercial machine in Samyang Milmax. The protein content of "Charmdlerak" was slightly higher than that of flour from Hard Red Winter Wheat (HRWW), the most popular multipurpose flour in Korea. The ash content and color of "Charmdlerak" wheat were similar to those of HRWW. End-use quality testing of cooked noodles and bread indicated that "Charmdlerak" flour resulted in softer noodles and similar bread loaf volume compared with products made from Keumkangmil wheat.

• Journal of Technologic Dentistry
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• v.34 no.2
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• pp.75-81
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• 2012

Purpose: All ceramic crown, made from zirconia instead of metal for core material, is recognized the best esthetical prosthesis. Recently, high-priced zirconia blocks and expensive CAD/CAM machines come into use for making zirconia core. In this study, slip casting process is adapted to evaluate the possibility of the recycling the remained parts of zirconia block after machining. Methods: Remained zirconia blocks were reduced to powders with zirconia mortar, and screened with 180 mesh sieve. Passed powders were ball milled under various conditions to obtain the optimum zirconia slip for casting. Solid casting method was used for casting the specimens with plaster mold. Formed specimens were dried and biscuit fired at $1,000^{\circ}C$ for 1 hour. Biscuit fired specimens were finished with exact shape of square pillar. Finished specimens were fired from $1,200^{\circ}C$ to $1,550^{\circ}C$ at $50^{\circ}C$ intervals for 1 hour. Linear shrinkage, apparent porosity, water absorption, bulk density, and flexural strength were tested. Microstructures were observed by SEM. Results: Above examinations indicated that the optimum firing temperture was $1,500^{\circ}C$, and when fired at this temperature for 1 hour, apparent porosity was 0% and flexural strength was 680MPa. SEM photomicrographs showed uniform 200~300nm grain size, which is equal with microcture of sintered commercial zirconia block. when compare 24% linear shrinkage of cast specimen with 20% linear shrinkage of CAD/CAM machined block, it was estimated that the size controlling of cast core was not so difficult. Conclusion: According to the all of this experimental results, the cast zirconia core produced from the remained parts of zirconia block was possible to use for all ceramic denture.

• Korean Journal of Food Science and Technology
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• v.19 no.6
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• pp.480-485
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• 1987

Quick cooking rice was produced by cooking raw, white long grain rice with three different methods which were atmospheric cooking in electric cooker, autoclaving and precooking followed by autoclaving. The drying rate curve showed that cooking methods affected little the drying pattern of the cooked rice except that precooking treatment before autoclaving retarded dehydration. The quick cooking rice prepared by precooking and autoclaving method among three cooking methods showed the fastest rehydration rate and took 7.5 minutes in reaching equilibrium moisture content by soaking in boiling water. And it had less hard and more cohesive texture than the milled rice cooked by conventional method and the quick cooking rice prepared by electric cooking when reconstituted. The microstructure of quick cooking rice was investigated among cooking methods.

• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.294-299
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• 1989

The quality of dehydrated instant rice produced by a few selected processing methods with short grain milled rice was evaluated. Instant rice produced by process 2 had high rehydration rate, and those by processes 1 and 2 revealed light brown color with less lightness. Instant rice produced by processes 1 and 2 with ammonium carbonate treatment had more uniform porous microstructure, as shown by SEM micrographes, and microstructural difference was noticed between instant rice prepared with government rice and Akibari. Instant rice produced by processes 1 and 2 had less sensory color score, and those by processes 2 and 4 had higher sensory cohesiveness. Overall quality of instant rice produced by process 2 was better, except color.